Safety control for presses



Feb. 15, 1949;

N. S. M EWEN SAFETY CONTROL FOR PREssEs 2 Sheets-Sheet 1 Filed Sept. 1, 1944 Feb. 15, 1949. N. s. MQEWEN 2,461,753

SAFETY CONTROL FOR PRESSES I 2 Sheets-Sheet 2 Filed Sept. 1, 1944 Ml'wen I .hanging head 3.

Patented Feb. 15, 949

UNIT-ED STAT ES 1 PATENT FFICE sAFE'rrcoNTaoL FORPRESSES v 7 Norman S. McEwen, Fort Lauderdale, Fla. Application s te gber 1, 1944, Serial No. 552.359

This invention relates to presses andmorepar-l ticularly to those having opposed dies iorimpa t inga'special formation to. one orimorefof the. surfacesof the piece of material. placed between. the dies, the invention having for its. object. to. provide a construction whichis simple. inf parts, less. costly to manufacture; and which provides a safety lock for rendering the apparatus in0pera.-.

tive exceptwhenthe pieceof material is corre itly positioned to. receive. the impression ofetheedies, V

' With these and other. objects in vie w, the fin-e vention resides in thenovel details oiconstruc' ti n an comb ati s of. parts. a will. be d skclosed more. fully hereinafter and; Particularl covered by the claims. f Referring to. the accompanying drawings. form,

ing a part'oi this specification and in which like numerals designate like. parts in all the views;

Fig. 1 .is a somewhat diagrammaticsideview of a press incorporating the features ofthls. invention; M

Fig. 2 is an enlarged detail view, partly in section, of the die actuatin mechanism and the safety mechanism for locking the control or such die actuating mechanism; p e

"Fig. 2a is a vertical sectional view on an enlarged scale in order better to illustrate the connection between the foot pedal and the slidable sleeve;

Fig. 3 is a perspective view of the parts shown in Fig. 2, said view being taken from a point-be- 4 Claims. (01. 19.2-42.9)

7 been shown as applied to a press adapted to make dimples or countersinks in one surface of a plate or sheet of metal, in registry with previously bored or punched holes, particularly in the case of holes adapted to receive flat. headed screws or rivets as for example in aluminum sheets for airplane construction or repair.

f'Ihe movable die is mounted at one end of a piston Soperating in a fluid pressure chamber l secured to the bed of the press, the other end of said piston being flared or otherwise formed to provide an enlarged flat head 8 to receive the pressure, of the applied fluid. The chamber, 1 is conveniently formed in two parts as shown, to

' as through the conduit mation of the press is immaterial. Consequently, 45

in Fig. 1 a somewhat diagrammatic representa tionof a commercial press is illustrated, said, press comprising a base or pedestal I, a bed gene erally identified by the numeral 2,; and an 0ver-- The relatively fixed die t iscarried by the. head 3, and the movable died is;

mounted upon the bed 2, these diesbeing of con figuration in QQnformity. with thework tobe. done. by them,

Throughout these, drawings. the. invention ha permit. the-placement and securement therebc tween ofasheet 9 of relatively thick rubber or other readily yieldable and stretchable material constituting a diaphragm in surface contact. with the flathead 8; of said piston.

A; pipelil is threaded into or otherwise secured at one end to the chamber so as to conduct a fluid under pressure to the diaphragm 9 and to cause said diaphragm to transmit such pressure to, the piston. and the movable die carried thereby.

. The. other end of said pipe communicates with a valve casing. generally identified by the numeral It, receiving fluid such as compressed air [2, said valve casing housing a'suitable valve mechanism operable as bydtllie pivoted link l3 actuated by the control r0 Betweenthe bed of the press and the floor there; is provided a guide rod 28 having slidably mounted thereon a'sleeve or tube 2B, the lower extremity of said tube carrying a lateral extension constituting a pedal 22. The control rod M isconnected to said tube as at 23:; and'a spring 24 is interposed between said'tube and the bed of the press to exert an upward pressure on said tube. The upper end of said tube carries a latch device 25,- such as a cone-shaped member as illustrated, and engages a stop collar 23 on the rod 2'flior limiting the upward travel of said tube. A pair of opposed standards and 3! are erected on opposite sides of the bed of the press, and to their upper extremities are pivotally secured the upper ends of the legs 32 and 33 respectively of astirrup, the connectin portion 34 oisaid stirrup extending beneath the bed of the. press and engageable with the latch device 25 her tofore mentioned. The stirrup hangs sub-e staritially. vertically, wherefore acoil spring 35 may be, attached to one. or its legs to urge the. stirrup toward and against the guide rod 20..

Therefore, the latch device, as well as the connecting portion of the stirrup may be, and preferably are, provided with cooperating bevelled surfaces as shown in order that the latch device may readily pass the stirrup in the upward movement of the valve control tube 21, and provided with fiat surfaces which immediately coengage after the latch device has thus snapped past the stirrup, resulting in a locked condition of the valve control and stirrup.

Near the upper end of the leg 32 of the stirrup is rigidly secured one branch 36 of a fork, and near the upper end of the other leg 33 of the stirrup is rigidly secured the other branch 3'! of the fork, the two branches meeting as at 38 and supporting a bifurcated member 39 straddling the movable die 5. Normally (i. e. when the press is not in use) this bifurcated member lies in a substantially horizontal plane about oneeighth of an inch below the tip of the movable die 5, as clearly shown in Fig. 2, wherefore a sheet of metal, with previously bored holesthat are to be dimpled or countersunk by this movable die, cannot touch and depress this bifurcated member until a bored hole has been brought into registry with said die. When such registry has been attained, the sheet of metal will fall and consequently depress said member and swing the stirrup to the position indicated in dotted lines at 48, to unlock the latch device and thus permit foot pressure, exerted upon the pedal, to move the valve control tube 2| downward, opening the valve and operating the press. Suitable leverage is provided in the fork and stirrup mounting, so that a downward movement of about one-quarter of an inch of the bifurcated member 39 will be more than ample to-swing the stirrup to unlock the latch 25.

As a precaution against the bifurcated memher being positioned too high relative the die 5 and so preventing a setting of the sheet metal with the tip of the die penetrating a previously bored hole in the sheet, the press may be provided with any suitable and well known type of adjusting screw for limiting the upward travel of said member. In the drawings, one such adjusting screw has been illustrated at 50, so positioned as to engage and stop the vertical leg 33 of the stirrup when said member reaches its correct upward position.

When large sheets are to be operated upon, auxiliary means may be provided for assisting in the support thereof during the actuation of the press. To this end there are shown duplicate work-supporting arms or rods, one on each side of the bed of the press, each capable of radial adjustment in conformity with the size of the sheet. That is to say, a vertical tube or socket is secured to said bed and within which is fitted the downwardly bent end portion 55 of the support rod 51, a nut 58 being threaded upon the lowermost end thereof.

So that the support rod may be held in adlusted radial position (with respect to the axis of the opposed dies), the upper extremity of said tube may be formed with a plurality of teeth or detents 59 of any desirable angular setting, to be coengaged by a complementally formed sin,- gle tooth or pawl 60 rigidly formed on or secured to the rod portion 56 (see Fig. 5). A spring 6| may be mounted upon the rod portion 56 be tween the lower extremity of said tube and the nut 58 to exert a pressure sufficient to prevent accidental disengagement of said pawl and detents.

As will be readily understood, radial movement of the support arm may be effected by exerting an upward force on the arm to disengage the holding teeth, and then swinging the arm to the desired position, and releasing said force to permit the spring 6! to seat and hold the teeth in engagement.

It is obvious that those skilled in the art may vary the details of construction and arrangements of parts without departing from the spirit of this invention, wherefore itis desired not to be limited to the exact foregoing disclosure except as may be required by the claims.

What is claimed is:

1. In a safety control for machines which include two opposed dies for operating upon an interposed piece of material, one of said dies being movable toward and away from the other die, and a member for actuating the movable die, the combination of control means for initiating movement of said member, said means comprising a sleeve slidable upon a fixed support, one end of said sleeve provided with an operating extension and the other end provided with one of a pair of companion latching members for normally holding said means in inoperative position; and pivoted release means for rendering said control means operable, said release means comprising one arm forming the other of the latching members and adapted to cooperatively engage and disengage with its companion member, and another arm having a portion positioned to be actuated by a piece of material only when the material is correctly interposed between said dies. 7

2. In a safety control for machines which include two opposed dies for operating upon an interposed piece of material, one of said dies being movable toward and away from the other die, and

a piston for moving the movable die; the combination of control means for initiating movement of the piston, said means comprising a yieldable diaphragm extensible under fluid pressure against the piston, a valve controlling a source of fluid pressure, and a slidable member provided with connecting linkage for operating said valve, one end of said member having a projection normally holding said means in inoperative position; and pivoted release means for rendering said control means operable, said release means comprising one arm adapted to cooperatively engage and disengage with said projection, and another arm having aportion positioned to be actuated by a piece of material only when the material is correctly interposed between said dies.

3. In a safety control for machines which include two opposed dies for operating upon an interposed piece of material, one of said dies being mounted upon the bed of the machine and movable in a direction toward and away from the other die, and a member for actuating the movable die, the combination of control means for initiating movement of said member, said means comprising a bevelled projection normally holding said means in inoperative position; and release means for rendering said control means operable, said release means comprising a stirrup having its legs pivotally mounted above, and upon opposite sides of, the bed of the machine and having its connecting portion passing beneath the having its opposite ends rigidly connected to the legs or said stirrup above the bed of the machine, the meeting ends of said fork carrying an extension positioned to be actuated by a piece of material only when the material is correctly interposed between said dies.

4. In a safety control for machines which include two opposed dies for operating upon an interposed piece of material, one of said dies bein movabletoward and away from the other die, and a member for actuating the movable die,'the combination of slidable control means for initiating movement of said member, said means normally being held in inoperative position; and release means for rendering said control means operable, said release means comprising a pivoted stirrup movable from one position to another, said stirrup when in one position underlying and holding inoperative a portion of said control means but when in its other position rendering said control means operable, said stirrup having a lateral H extension for swinging said stirrup from its inoperative holding position to its operable releasing position, said extension positioned to be actuated by the weight of a piece of material only when the material is correctly interposed between said dies.

NORMAN S. McEWEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 1 Date 945,992 Stevens Jan. 11, 1910 1,050,185 Watres Jan. 14, 1913 1,229,792 Russell June 12, 1917 1,369,690 Metzger Feb. 22, 1921 1,479,733 Quinn Jan. 1, 1924 1,549,072 Dole Aug. 11, 1925 1,712,657 Frankenberg May '14, 1929 1,804,599 Edel May 12, 1931 1,856,290 Prusseng May 3, 1932 1,937,314 Bryant Nov. 28, .1933 2,017,865 Morgan Oct. 22, 1935 2,288,378 Veit June 30, 1942 2,324,660 Yanchenko July 20, 1943 2,328,919 Merriman Sept. 7, 1943 2,333,418 Fischer Nov. 2, 1943 2,344,944 Hurst Mar. 28, 1944 2,371,358 Sekella Mar. 13, 1945 FOREIGN PATENTS Number Country Date 832,915 France Oct. 6, 1938 

